pontiac engine noise, possibly rod knock? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 08-06-2006, 08:04 AM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
pontiac engine noise, possibly rod knock?

After taking the front of the engine apart and degreeing the cam, my father and I finally dropped the distributor in and fired it up. The engine started right up and seemed to run rather well, except for valve clatter. So we took the valve covers off and put a 1/4 more turn on the self locking nuts. Started the engine and valve clatter was gone, but now we can hear a faint thumping noise.

Before we degreed the cam we also heard some kind of noise, but dismissed it and went ahead and degreed the cam. Also looking back, when I was rotating the engine over, with no plugs in it, to adjust the valves ever once in a while you could feel a clunk through the wrench. It kind of felt like something was not moving, then all of a sudden it was moved.

Back to the present, when the engine is cranking over I can hear a noise that goes: thump a dump, thump a dump, thump a dump. then when the engine is running you can hear a very faint knocking sounds that goes with engine rpm but does not get any louder.

I just watched some vids on youtube of rod knock, it kind of sounds like that except it is way way softer. If you stand back a couple feet I doubt you could hear it. We had the engine rebuilt this spring. The shop did the short block. All we did was put the oil pump/pan on, install the cam, heads, intake and thats about it. I know the oil pump works, I primed it before the first firing and watched oil come up through all of the push rods. I double checked that the dist. is engaged with the oil pump. All I can think of is either a collapsed lifter or rod knock(which is a spun bearing right?).

So is there any harm in running it any more? What could be wrong? any easy ways to check for the problem that does not involve engine removal?

any help would be great!!

thanks,

Matt

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-06-2006, 08:10 AM
Lonestar's Avatar
"May the Schwartz be with you"
 
Last wiki edit: How to rebuild an engine
Last journal entry: Finally getting going...
Last photo:
Join Date: Aug 2004
Location: United States
Age: 43
Posts: 1,054
Wiki Edits: 1

Thanks: 0
Thanked 0 Times in 0 Posts
You can rule out rod knock by starting the engine and pulling spark plug wires one at a time to see if the noise decreases in intensity or goes away...this will also tell which cylinder (if any) that the noise is coming from.

From your description it does not sound to me like a rod...how about crank to oil pan clearance, torque converter bolts, accessory bolts...I would look at all those.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-06-2006, 11:42 AM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
We went back and made sure all of these acessories were tight, they were. Fired it up and still have the knocking noise.

So we removed the belt so the only thing turning was the crank. Still have the noise.

So we removed the fuel pump. Still have the noise.

I will go back and check the torque converter bolts next, but I feel the noise is coming from the front of the engine.

Any Ideas? I sure hope its not a rod bearing, the engine does not even have 30 miles on it, probibly less then 3 hours run time, and never went past 3000rpm.

any help would be great!

thanks

Matt
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-06-2006, 12:28 PM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I was also thinking the the lifters might be toast. Originaly we used the factory rocker nuts and torqued them to 20 ft/lbs like the factor says. So when we switched to self locking nuts after degreeing the cam we used the standard zero lash then half turn more procedure. This is on a crane blueprint 068 cam with hydrulic lifters. when we frist started it up it sounded like a sewing machine, lost of clatering, worse then my friends mechanical cam. So the next day(today) to added a little bight to each rocker, about 1/4 turn, and fired it up. Now the rocker arm noise is gone but there is a knocking nosie.

I should add that when we were adjusting the rockers to zero lash the lifters seemed hard. On my sbc you can puch on the rocker and feel the spring inside the lifter as you push it. Now on the pontiac only a few lifters would do that, the rest seemed hard as a rock, no movement.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-06-2006, 02:01 PM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
After reading some old posts I figure we might have chevy lifter in there instead of pontiac, although I am quite sure they were pontiac lifters. So we went a took a valve cover off and started the motor. After about 1.5 mintues there was still no oil coming out of the pushrods, somethings not right.

So, Since I don't trust the oil dumby light, I unscrewed it and put in a guage. At an idle it is making a little over 10psi maybe 15psi. When the engine is reved its about 30psi max. So I know the dist is turning the pump shaft and the shaft is turning the oil pump, but it is not making any pressure!!!

The oil pump is a new m54ds melling pump. I figure the lifters are probibly toast and maybe the cam I guess. I just hope the rotating assembly is not junk.

what do I do next? any help would be great!!
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
crate chevy 302? Vancouver Grand Prix Hotrodders' Lounge 106 12-31-2012 04:05 PM
Engine valvetrain tap sy733 Engine 19 12-17-2005 12:09 PM
rod knock StevenC Engine 8 12-07-2005 10:51 PM
will a 1969 455ci olds engine bolt right in place of a pontiac 400??? chevyelc81 Engine 3 06-12-2002 03:54 AM
Engine choice for old Pontiac BigChief Engine 4 01-29-2002 07:51 PM


All times are GMT -6. The time now is 04:49 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.